Camera flash systems and methods for adjusting flash exposure power

ABSTRACT

Camera flash systems and methods for data transmission between cameras and flash devices remote to the camera for remotely adjusting flash exposure power of the flash devices are disclosed. The camera flash systems include a transmitter and a receiver. The transmitter receives camera output data from a camera that includes exposure power data for at least one flash device remote to the transmitter and user input data that includes adjustments to the flash exposure power data for the at least one flash device. The transmitter is operable to transmit the adjusted flash exposure power data to the at least one flash device. The receiver receives the adjusted flash exposure power data from the transmitter and is operable to transmit the adjusted flash exposure power data to a flash device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 13/527,916, filed Jun. 20, 2012 and claims thebenefit of U.S. Provisional Application No. 61/536,319 filed on Sep. 19,2011, the contents of which are incorporated fully herein by reference.

FIELD OF THE INVENTION

The invention relates to the control of remote flash devices, and moreparticularly, to data transmission systems used between cameras andflash devices remote to the cameras for remotely adjusting flashexposure power for the flash devices.

BACKGROUND OF THE INVENTION

In conventional photography, a single camera may be able to wirelesslysupport one or more remote flash devices. Each flash device has anexposure power which regulates the intensity of the flash produced bythe flash device. The flash exposure power for the flash device may becontrolled manually, or may be controlled automatically using thecamera. In particular, the camera may be used to calculate and controlthe remote flash devices' exposure power, by “through-the-lens” (TTL)mode.

In TTL mode, a camera will wirelessly transmit pre-flash instructions,which cause the remote flash devices to flash according to a certainpower level. The camera will analyze the exposure power of the pre-flashand calculate a suitable brightness value for the formal exposure (i.e.,for the photograph). The camera will then send the desired flashexposure power to the remote flash devices before the formal exposure.

Despite the benefits associated with conventional TTL mode, improvementsin the control of flash exposure power are desired.

SUMMARY OF THE INVENTION

The present invention is embodied in camera flash systems and methodsfor data transmission between cameras and flash devices remote to thecamera for remotely adjusting flash exposure power of the flash devices.The camera flash systems include a transmitter and a receiver. Thetransmitter receives camera output data from a camera that includesexposure power data for at least one flash device remote to thetransmitter and user input data that includes adjustments to the flashexposure power data for the at least one flash device. The transmitteris operable to transmit the adjusted flash exposure power data to the atleast one flash device. The receiver receives the adjusted flashexposure power data from the transmitter and is operable to transmit theadjusted flash exposure power data to a flash device.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawings, with likeelements having the same reference numerals. When a plurality of similarelements are present, a single reference numeral may be assigned to theplurality of similar elements with a small letter designation referringto specific elements. When referring to the elements collectively or toa non-specific one or more of the elements, the small letter designationmay be dropped. This emphasizes that according to common practice, thevarious features of the drawings are not drawn to scale unless otherwiseindicated. On the contrary, the dimensions of the various features maybe expanded or reduced for clarity. Included in the drawings are thefollowing figures:

FIG. 1 is a block diagram of a transmitter for an exemplary camera flashsystem for adjusting flash exposure power in accordance with aspects ofthe present invention;

FIG. 2 is a block diagram of a receiver for an exemplary camera flashsystem for adjusting flash exposure power in accordance with aspects ofthe present invention;

FIG. 3 is an image of the transmitter of FIG. 1; and

FIG. 4 is a block diagram of a camera flash system for adjusting flashexposure power in accordance with aspects of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the present invention are directed to data transmissionsystems for use between cameras and flash devices remote to the camerasfor remotely adjusting flash exposure power of the flash devices(referred to herein as camera flash systems). Generally, it makes itpossible for cameras operating in TTL mode to adjust exposure power forcompatible remote flash devices individually or in groups.

In accordance with one aspect of the present invention, a camera flashsystem configured for adjusting flash exposure power is disclosed. Thecamera flash system includes a transmitter (e.g., as shown in FIG. 1)and a receiver (e.g., as shown in FIG. 2). Referring to the figuresgenerally, the transmitter comprises a transmitter connecting element11, a user input unit 15, and a transmitting unit 16. The transmitterconnecting element is configured for coupling the transmitter to acamera (not shown). The transmitter is operable to receive data outputby the camera (“camera output data”) via the transmitter connectingelement 11. The camera output data includes flash exposure power datafor at least one remote flash device. The user input unit 15 isconfigured to receive user input data from a user of the camera flashsystem. The user input data includes adjustments to the flash exposurepower data for at least one flash device remote to the transmitter. Thetransmitting unit 16 is operable to transmit the adjusted flash exposurepower data (via a transmitting element 16 a such as RF circuitry and anantenna 16 b) to the at least one flash device. The receiver comprises areceiving unit 21 and a receiver connecting element 26. The receivingunit 21 is operable to receive the adjusted flash exposure power datafrom the transmitter (via antenna 21 b and receiving element 21 a suchas RF circuitry). The receiver connecting element 26 is configured forcoupling the receiver to a flash device. The receiver is operable tosend the adjusted flash exposure power data to the flash device via thereceiver connecting element 26.

Preferably, the camera flash system includes one or more groups of flashdevices remote to the transmitter. Each group includes one or more flashdevices. The one or more flash device of each group having an associatedreceiver. The camera output data comprises a set of flash exposure powerdata for each of the group(s) of flash devices. The user input datacomprises adjustments to each set of flash exposure power data. Morepreferably, the transmitter is operable to transmit each set of adjustedflash exposure power data separately, and the receiver is operable toreceive the adjusted flash exposure power data for the group of flashdevices with which its receiver is associated.

Preferably, the transmitter is operable to receive pre-flash data fromthe camera via the transmitter connecting element 11. The pre-flash datacomprises instructions to at least one flash device to perform a flashoperation. The transmitting unit 16 is further operable to transmit thepre-flash data to at least one flash device.

Preferably, the adjusted flash exposure power data transmitted by thetransmitting unit 16 includes instructions to at least one flash deviceto perform a flash operation using the flash exposure power provided inthe adjusted flash exposure power data.

In accordance with another aspect of the present invention, a method foradjusting flash exposure power is disclosed. The method includesreceiving camera output data from a camera at a transmitter, the cameraoutput data including flash exposure power data for at least one groupof flash devices, receiving user input data from a user at thetransmitter, the user input data including adjustments to the flashexposure power data for the at least one group of flash devices, andtransmitting the adjusted flash exposure power data to the at least onegroup of flash devices.

With reference to the drawings, FIG. 4 discloses a camera flash systemfor independently grouping and adjusting the flash exposure power of atleast one flash device, in accordance with aspects of the presentinvention. The system is operable to independently group a camera'sthrough-the-lens (TTL) exposure power calculations, and to wirelesslytransmit them to flash devices after adjustment.

A transmitter of the above-described system is shown in FIG. 1. Thetransmitter includes a connecting element 11 for connection to a camera.The connecting element 11 may be adapted to connect via a hot shoeconnector on the camera. The transmitter further includes signalprocessing unit 12 for processing signals received from the camera. Thetransmitter includes one or more visual feedback device(s) 13 (e.g., amonitor and/or an LED) for providing feedback to a user regarding theoperation of the transmitter. The transmitter includes a microprocessor14 for controlling the operation of the transmitter and performing thefunctions recited herein. The transmitter includes a user input unit 15(e.g., a keyboard) for enabling input of data from a user (e.g.,adjustment data). Finally, the transmitter includes a transmitting unit16 for wirelessly transmitting data (e.g., flash exposure power data viaa transmitting element 16 a and an antenna 16 b) to correspondingreceivers at flash devices remote to the transmitter.

The disclosed transmitter may obtain TTL automatic exposure power datumvia a connecting element 11 adapted to connect to the camera's hot shoeconnector. In accordance with one aspect of the present invention, thetransmitter independently groups the camera's exposure power datum foreach group of remote flash devices using microprocessor 14, andwirelessly transmits them to the flash devices using transmitting unit16 after enabling adjustment by a user (e.g., through a user input unit15 such as a keyboard). Accordingly, each group of flash devices canadjust their exposure power independently, without affecting theexposure power of flash devices in other groups. Additionally, thedisclosed transmitter enables the combination of flash devices operatingin manual exposure mode together with flash devices operating inautomatic exposure mode.

A receiver of the above-described system is shown in FIG. 2. Thereceiver includes a receiving unit 21 which is the counterpart of thetransmitting unit 16 of the transmitter. The receiving unit 21 isconfigured for wirelessly receiving data (e.g. flash exposure power datavia antenna 21 b and receiving element 21 a) at the flash device(s)remote to the transmitter. The receiver includes one or more visualfeedback device(s) 22 (e.g., an LED status indicator) for providingfeedback to a user regarding the operation of the receiver. The receiverincludes a microprocessor 23 for controlling the operation of thereceiver and performing the functions recited herein. The receiver alsoincludes one or more switches 24 for switching the remote flash devicegroup with which the remote flash device is associated and/or switchingthe channel on which the receiver receives signals from the transmitter.The receiver further includes signal processing unit 25 for processingsignals to be sent to the flash device. Finally, the receiver includes aconnecting element 26 for connection to the flash device. The connectingelement 26 may be adapted to connect via a hot shoe connector on theflash device.

As shown in FIG. 3, the transmitter includes button controls and an LCDto adjust the mode, power levels, and functions of flash devices remoteto the transmitter.

An exemplary operation of the system for adjusting flash exposure poweris described herein. First, the transmitter reads a pre-flashinstruction sent out by the camera, and transmits it to the receiver orplural receivers. After the receiver(s) get the pre-flash instructions,it/they will give notice to the flash device to perform the pre-flash.After the flash devices perform the flash operation, the camera catchesthe brightness of the pre-flash, through TTL monitoring. The camera willthen calculate the flash exposure power of each group of flash devices(e.g., three groups of flash devices: A, B, C). Next, the transmitterreceives the flash exposure power data from the camera via the hot shoeof the camera. After the transmitter independently receives the flashexposure power data for each group, the data of each group is adjustedaccording to the values entered by the user on the transmitterbuttons/LCD of the transmitter. For example, the user can choose to addlight, reduce light or make no adjustment to the flash exposure powercalculated by the camera. The adjusted flash exposure power is thentransmitted to the receiver(s) wirelessly, e.g., by RF signal.

After the receiver receives the adjusted flash exposure power data, theadjusted exposure power data is transmitted to the flash device via thehot shoe connector of the flash device. The flash device may then flashsynchronously with other flash devices based on the adjusted flashexposure power.

By using wireless remote control technology to remotely control theflash devices, aspects of the present invention achieve automaticphotometry with independent grouping and adjustment of exposure power.

In an exemplary embodiment the system includes a plurality of receivers,with each receiver associated with a flash device. The flash devices maybe grouped into one or more (e.g., three) groups of flash devices. Eachflash device may be independently set in TTL mode or manual mode. In anexemplary embodiment, in manual mode, the available exposure powers mayinclude:1/1,1/1-1/3,1/1-2/3,1/2,1/2-1/34/2-2/34/44/4-1/34/4-2/34/84/8-1/34/8-2/34/16,1/16-1/3,1/16-2/34/32,1/32-1/34/32-2/34/64,1/64-1/34/64-2/3,1/128.In the exemplary embodiment, in TTL mode, the adjustment of the exposurepower automatically calculated by the camera may include: −3.0 Ev, −2.7Ev, −2.3 Ev, −2.0 Ev, −1.7 Ev, −1.3 Ev, −1.0 Ev, −0.7 Ev, −0.3 Ev, +0Ev, +0.3 Ev, +0.7 Ev, +1.0 Ev, +1.3 Ev, +1.7 Ev, +2.0 Ev, +2.3 Ev, +2.7Ev, +3.0 Ev (where “Ev” stands for “Exposure value”).

The system may be configured such that it is necessary to take onephotograph for the transmitter and receiver pair to properly perform theTTL monitoring.

Exemplary functions of aspects of the present invention are set forthbelow.

The transmitter has at least two function screens: TTL/Mixed (shown inFIG. 3) and Ratio. TTL/Mixed allows groups A, B and C to be set to TTL,Manual, or OFF with adjustments to Ev or power levels. In the Ratioscreen, the ratio of groups A and B can be set from 8:1 to 1:8 forexample. Ev levels can also be adjusted. An option button on thetransmitter may be actuated to change between function screens.

The transmitter may include a Selection Button 17 that allows a user tocycle through groups A, B, and C, and Channel selections. The adjustmentbuttons 18 on the transmitters will enable a user to change the EVadjustments or Power Level while groups A, B or C are selected and willchange the transmission channel (1, 2, 3 or 4) when Channel is selected.This will change the channel the transmitter uses to transmit. Thetransmitter will work on the last channel which was adjusted. For theRation function screen, the Selection Button 17 allows a user to cyclethrough ratio A:B adjustment, EV adjustment and Channel selections.

The transmitter further includes a test button 19. The test buttonenables a user to fire all flashes connected to receivers that are onthe same channel as the transmitter. Pressing the Test button may enablethe remote flash devices to fire in sequence: Group A, followed byGroups B and C.

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

What is claimed:
 1. A camera flash system configured for remotelyadjusting flash exposure power comprising: a transmitter comprising: atransmitter connecting element configured for coupling the transmitterto a camera, the transmitter being operable to receive camera outputdata from the camera via the transmitter connecting element, the cameraoutput data including flash exposure power data for at least one flashdevice remote to the transmitter; a user input unit configured toreceive user input data from a user of the camera flash system, the userinput data including adjustments to the flash exposure power data forthe at least one flash device; and the transmitter being operable totransmit the adjusted flash exposure power data to the at least oneflash device; and a receiver comprising: a receiving unit operable toreceive the adjusted flash exposure power data from the transmitter; anda receiver connecting element configured for coupling the receiver toone of the at least one flash device, the receiver being operable totransmit the adjusted flash exposure power data to the one of the atleast one flash device via the receiver connecting element.
 2. Thecamera flash system of claim 1, further comprising one or more groups offlash devices remote to the transmitter, each group including one ormore flash devices, the one or more flash device of each group having anassociated receiver; wherein the camera output data comprises a set offlash exposure power data for each of the one or more groups of flashdevices; and the user input data comprises adjustments to each set offlash exposure power data.
 3. The camera flash system of claim 2,wherein: the transmitter is operable to transmit each set of adjustedflash exposure power data separately; and the receiver is operable toreceive the adjusted flash exposure power data for the group of flashdevices with which its receiver is associated.
 4. The camera flashsystem of claim 1, wherein: the transmitter is further operable toreceive pre-flash data from the camera via the transmitter connectingelement, the pre-flash data comprising instructions to the at least oneflash device to perform a flash operation; and the transmitter isfurther operable to transmit the pre-flash data to the at least oneflash device.
 5. The camera flash system of claim 1, wherein theadjusted flash exposure power data transmitted by the transmitterfurther comprises instructions to the at least one flash device toperform a flash operation using the flash exposure power provided in theadjusted flash exposure power data.
 6. A transmitter configured forremotely adjusting flash exposure power in a camera flash system, thetransmitter comprising: a transmitter connecting element configured forcoupling the transmitter to a camera, the transmitter being operable toreceive camera output data from the camera via the transmitterconnecting element, the camera output data including flash exposurepower data for at least one flash device remote to the transmitter; auser input unit configured to receive user input data from a user of thetransmitter, the user input data including adjustments to the flashexposure power data for the at least one flash device; and thetransmitting unit operable to transmit the adjusted flash exposure powerdata to the at least one flash device.
 7. The transmitter of claim 6,wherein: the user input unit is configured to receive user input dataincluding adjustments to the flash exposure power data for a pluralityof groups of flash devices remote to the transmitter, each groupcomprising one or more flash devices; the camera output data comprises aset of flash exposure power data for each of the plurality of groups offlash devices; and the user input data comprises adjustments to each setof flash exposure power data.
 8. The transmitter of claim 7, wherein:the transmitter is operable to transmit each set of adjusted flashexposure power data separately.
 9. The transmitter of claim 6, wherein:the transmitter is further operable to receive pre-flash data from thecamera via the transmitter connecting element, the pre-flash dataincluding instructions to the at least one flash device to perform aflash operation; and the transmitter is further operable to transmit thepre-flash data to the at least one flash device.
 10. The transmitter ofclaim 6, wherein the adjusted flash exposure power data transmitted bythe transmitter further comprises instructions to the at least one flashdevice to perform a flash operation using the flash exposure powerprovided in the adjusted flash exposure power data.
 11. A method forremotely adjusting flash exposure power comprising: receiving cameraoutput data from a camera at a transmitter, the camera output dataincluding flash exposure power data for at least one flash device remoteto the camera; receiving user input data from a user at the transmitter,the user input data including adjustments to the flash exposure powerdata for the at least one flash device; and transmitting the adjustedflash exposure power data to the at least one flash device.
 12. Themethod of claim 11, wherein: the step of receiving camera output datacomprises receiving camera output data including a set of flash exposurepower data for each of a plurality of groups of flash devices remote tothe transmitter, each group comprising one or more flash devices; andthe step of receiving user input data comprises receiving user inputdata including adjustments to each set of flash exposure power data. 13.The method of claim 12, wherein: the transmitting step comprisestransmitting each set of adjusted flash exposure power data separately.14. The method of claim 11, further comprising the steps of:communicating pre-flash data from the camera to the transmitter, thepre-flash data including instructions to the at least one flash deviceto perform a flash operation; and transmitting the pre-flash data to theat least one flash device.
 15. The method of claim 11, furthercomprising the step of: transmitting instructions to the at least oneflash device to perform a flash operation using the flash exposure powerprovided in the adjusted flash exposure power data.